Biomedical subjects

M Iwai

Publications and source records attributed to M Iwai.

At least 37 records · Page 2Linked to original sources

PubMed2002

Immunohistochemical localization of CEA, CA19-9 and DU-PAN-2 in hepatitis C virus-infected liver tissues.

AIMS: We investigated expression of CEA, CA19-9 and DU-PAN-2 in liver tissues of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma, measuring their serum value to clarify their clinical significance, and proliferating cell nuclear antigen (PCNA) was assessed in serial sections to determine whether expression of these molecules in chronic liver disease was related to regeneration of biliary ducts. METHODS AND RESULTS: Liver tissues were biopsied under peritoneoscopy or echo-guidance and resected surgically among 63 patients with anti-hepatitis C virus-positive sera. There were 26 cases of chronic hepatitis, 21 cases of liver cirrhosis and 16 cases of hepatocellular carcinoma (four cases of mixed type). They were simultaneously used for immunocytochemistry for CEA, CA19-9 and DU-PAN-2, and PCNA was demonstrated in serial liver tissues by immunohistochemistry. Serum CEA, CA19-9 and DU-PAN-2 were measured by radioimmunoassay or enzyme immunoassay. In chronic hepatitis and liver cirrhosis CEA immunoreactivity was seen on membranes facing bile canaliculi and in bile ductules. Both CA19-9 and DU-PAN-2 immunoreactivity were observed in bile ductules in chronic hepatitis liver cirrhosis and non-neoplastic areas surrounding hepatocellular carcinoma, and CA19-9 was also present in interlobular bile ducts. PCNA immunoreactivity was not detected in marker-positive bile ductules or interlobular bile ducts. In hepatocellular carcinoma CEA immunoreactivity was seen on membrane facing dilated bile canaliculi in glandular structures, and CEA, CA19-9 and DU-PAN-2 immunoreactivity was observed in cholangiolar areas in mixed type of hepatocellular carcinoma. CONCLUSIONS: CEA in chronic hepatitis and liver cirrhosis is expressed not only in bile ductules but also on membrane facing bile canaliculi, and both CA19-9 and DU-PAN-2 were seen in different levels of biliary ducts. These molecules were expressed in bile ductules in surrounding non-neoplastic areas of hepatocellular carcinoma, and their expression was not associated with regeneration of biliary ducts. CEA expression was present in the trabecular type of hepatocellular carcinoma, and CA19-9 and DU-PAN-2 were observed in cholangiolar areas in mixed type of hepatocellular carcinoma.

Antigens, Neoplasm↗

PubMed2002

Temporal and spacial changes of BrdU immunoreactivity in amygdala kindling development.

To investigate the proliferation of neural stem cells (NSC) in epileptic brain, spaciotemporal expression of immunoreactive bromodeoxyuridine (BrdU) was examined in kindling development of rat. Amygdaloid kindling in partial seizure (PS) was effective in proliferation of NSC detected with BrdU-labeling in subventricular zone (SVZ), but not in dentate gyrus (DG). In SVZ, however, the BrdU-labeling cells decreased at stage generalized seizure (GS). These facts indicate that proliferation of NSC increased with PS and decreased with more severe seizures of GS in SVZ, that such a proliferation did not occur in DG with PS or GS. Thus, the proliferation of NSC was spacially and temporally different between brain regions depending on different kindling stages.

Amygdala↗

PubMed2001

Temporal and spatial differences of PSA-NCAM expression between young-adult and aged rats in normal and ischemic brains.

Highly polysialylated neural cell adhesion molecule (PSA-NCAM) is transiently expressed specifically in newly generated cells, and is important for migration and neurite outgrowth. To investigate the effect of aging on the migration of neural stem cell (NSC) after brain ischemia, the spatiotemporal expressions of immunoreactive PSA-NCAM were examined at 4 h or 1, 3 or 7 days after 90 min of middle cerebral artery occlusion (MCAO) in the young-adult or aged rats. In the sham control brain, PSA-NCAM staining was slightly observed both in dorsal and ventral parts of subventricular zone (SVZ) in the aged brain, but only in the dorsal part of SVZ in the young brain. After transient MCAO, immunoreactivity for PSA-NCAM increased in the number and the intensity in SVZ ipsilateral to MCAO in the young-adult brains and became the peak at 1 day, while that was at 3 days in the aged brains. These findings suggest that PSA-NCAM was located in different spatial distribution in normal condition between young and old rats. PSA-NCAM was induced after ischemia, and the temporal expression was also different after transient MCAO between young and older rats.

Aging↗

PubMed2001

Roles of angiotensin II type 2 receptor stimulation associated with selective angiotensin II type 1 receptor blockade with valsartan in the improvement of inflammation-induced vascular injury.

BACKGROUND: To investigate the effect of angiotensin (Ang) II type 1 receptor (AT(1)) blocker on vascular remodeling and explore the possibility of the involvement of Ang II type 2 receptor (AT(2)) stimulation in this process, we examined the effects of the selective AT(1) blocker valsartan on the vascular injury in wild-type (Agtr2+) and AT(2)-null (Agtr2-) mice. METHODS AND RESULTS: Neointima formation and the proliferation of vascular smooth muscle cells (VSMCs) induced by cuff placement on the femoral artery were greater in Agtr2- mice than those in Agtr2+ mice. Treatment of mice with valsartan at a dose of 1 mg. kg(-1). d(-1), which did not influence systolic blood pressure, significantly decreased neointima formation and the proliferation of VSMCs, whereas the valsartan was less effective in Agtr2- mice. Moreover, cuff placement increased the expression of monocyte chemoattractant protein-1 (MCP-1); inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-1beta; and infiltration of CD45-positive leukocytes and macrophages in the injured arteries and further enhanced them in Agtr2- mice, suggesting the antagonistic effects of AT(1) and AT(2) for vascular inflammation. Valsartan attenuated the expression of MCP-1, TNF-alpha, IL-6, IL-1beta, and infiltration of leukocytes and macrophages in the injured arteries; however, these effects of valsartan were less prominent in Agtr2- mice. CONCLUSIONS: These results suggest that the stimulation of the AT(2) receptor after AT(1) blockade is important in the improvement of the inflammatory vascular injury.

Angiotensin I↗

PubMed2001

Expression of polysialylated neural cell adhesion molecule in rat brain after transient middle cerebral artery occlusion.

The highly polysialylated form of neural cell adhesion molecule (PSA-NCAM) is important for neurite outgrowth. With this molecule as a marker of plastic change in neurons, we investigated its temporal expression in rat brain after transient middle cerebral artery (MCA) occlusion. In sham-control brain, only subependymal neurons showed a positive immunoreactivity for PSA-NCAM. After 90 min of transient MCA occlusion, neurons in the piriform cortex began to be positively stained at 1 h, while neurons in the cortex and caudate of the MCA territory became positive after 8 h. The stainings persisted for 1 and 3 days after reperfusion. The present results indicate that neurons in the cerebral cortex and caudate have the capability of plastic change in the adult brain, and that those in the piriform cortex rapidly undergo plastic change probably in response to transneuronal injury.

Animals↗

PubMed2001

Time dependent amelioration against ischemic brain damage by glial cell line-derived neurotrophic factor after transient middle cerebral artery occlusion in rat.

Time dependent influence of glial cell line-derived neurotrophic factor (GDNF) was examined after 90 min of transient middle cerebral artery occlusion (MCAO) in rats. Treatment with GDNF significantly reduced the infarct volume stained with 2,3,5-triphenyltetrazolium chloride (TTC) when GDNF was topically applied at 0 and 1 h of reperfusion, but became insignificant at 3 h as compared to vehicle group. The protective effect of GDNF was closely related to the significant reduction of the number of terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling (TUNEL) positive cells as well as immunofluorescently positive cells for active forms of caspases, especially active caspase-3 but not -9. Thus, the present study showed that topical application of GDNF significantly reduced infarct size in a time-dependent manner, while the therapeutic time window was shorter than other chemical compounds such as an NMDA receptor antagonist (MK-801) and a free radical scavenger (alpha-phenyl-tert-butyl-nitrone, PBN). The effect of GDNF was stronger in suppressing active caspase-3 than active caspase-9.

Animals↗

PubMed2001

Induction of highly polysialylated neural cell adhesion molecule (PSA-NCAM) in postischemic gerbil hippocampus mainly dissociated with neural stem cell proliferation.

We investigated a possible expression of highly polysialylated neural cell adhesion molecule (PSA-NCAM) in gerbil hippocampus after 5 min of transient global ischemia in association to the proliferation of neural stem cell labeled with bromodeoxyuridine (BrdU). The number of PSA-NCAM positive cells increased in the granule cell layer (GCL) of dentate gyrus (DG) by 1.9 to 2.7-fold at 10 and 20 days after the reperfusion. The number of BrdU-labeled cells increased mainly in the subgranular zone of DG by 7.2 to 8.0-fold at 5 and 10 days after the reperfusion. Immunofluorescence for PSA-NCAM and BrdU showed that the majority of DG cells were not double labeled, while one or two cells per section were double labeled in the deepest portion of the GCL only at 10 days after the reperfusion. These results suggest different predominant spatial distribution and chronological change of PSA-NCAM positive and BrdU-labeled cells in DG after transient ischemia.

Animals↗

PubMed2001

Measurement of the CP violation parameter sin2 phi(1) in B(0)(d) meson decays.

We present a measurement of the standard model CP violation parameter sin2 phi(1) (also known as sin2beta) based on a 10.5 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) collider. One neutral B meson is reconstructed in the J/psiK(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psiK(L), or J/psipi(0) CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its charged particle decay products. From the asymmetry in the distribution of the time interval between the two B-meson decay points, we determine sin2 phi(1) = 0.58(+0.32)(-0.34)(stat)+0.09-0.10(syst).

Journal Article↗

PubMed2001

Increased secretion of tumour necrosis factor and interleukin 6 from isolated, perfused liver of rats after partial hepatectomy.

The present study explored the changes in hepatic secretion of tumour necrosis factor (TNF) and interleukin 6 (IL-6) during the regenerative process of the liver, focusing on the role of Kupffer cells. The secretions of TNF and IL-6 from the perfused rat liver were increased after 67% partial hepatectomy, reaching a maximum at 48 h. The response of cytokine secretion induced by lipopolysaccharide (LPS: 1 microgram/ml) was also potentiated in regenerating liver. The secretion of TNF, but not that of IL-6, induced by LPS was almost totally suppressed by pretreatment of rats with gadolinium chloride, which depletes Kupffer cells. These results indicate that hepatic secretions of TNF and IL-6 are increased during the regenerative process of the liver. Kupffer cells play an important role in hepatic secretion of TNF, whereas the production of IL-6 can be achieved by other cells of the liver.

Animals↗

PubMed2001

Evaluation of hydration states of protein in freeze-dried amorphous sugar matrix.

A model to analyze the hydration state of protein in freeze-dried amorphous sugar matrix was proposed, based on the assumptions that there is a limit to the amount of protein that a given amount of amorphous sugar could embed and that the freeze-dried sugar-protein mixture is composed of the four components, i.e., sugars with and without hydrogen bonding to proteins and proteins with and without hydrogen bonding to sugar. Bovine serum albumin and three kinds of disaccharides, i.e., sucrose, maltose, and trehalose, were used as samples. Using the analytical equations derived from the model and experimental sugar content dependencies of the water sorption at various relative humidities, the amount of hydration water for bovine serum albumin, and the minimum amount of sugar to embed the protein were determined. On the basis of these results, the degree of interaction between the three sugars and protein was discussed, with respect to their stabilizing effect on the protein.

Carbohydrates↗

PubMed2001

Experimental study of vascularized nerve graft: evaluation of nerve regeneration using choline acetyltransferase activity.

A comparative study of nerve regeneration was performed on vascularized nerve graft (VNG) and free nerve graft (FNG) in Fischer strain rats. A segment of the sciatic nerve with vascular pedicle of the femoral artery and vein was harvested from syngeneic donor rat for the VNG group and the sciatic nerve in the same length without vascular pedicle was harvested for the FNG group. They were transplanted to a nerve defect in the sciatic nerve of syngeneic recipient rats. At 2, 4, 6, 8, 12, 16, and 24 weeks after operation, the sciatic nerves were biopsied and processed for evaluation of choline acetyltransferase (CAT) activity, histological studies, and measurement of wet weight of the muscle innervated by the sciatic nerve. Electrophysiological evaluation of the grafted nerve was also performed before sacrifice. The average CAT activity in the distal to the distal suture site was 383 cpm in VNG and 361 cpm in FNG at 2 weeks; 6,189 cpm in VNG and 2,264 cpm in FNG at 4 weeks; and 11,299 cpm in VNG and 9,424 cpm in FNG at 6 weeks postoperatively. The value of the VNG group was statistically higher than that of the FNG group at 4 weeks postoperatively. Electrophysiological and histological findings also suggested that nerve regeneration in the VNG group was superior to that in the FNG group during the same period. However, there was no significant difference between the two groups after 6 weeks postoperatively in any of the evaluations. The CAT measurement was useful in the experiments, because it was highly sensitive and reproducible.

Action Potentials↗

PubMed2001

Glucagon attenuates the action of insulin on glucose output in the liver of the Goto-Kakizaki rat perfused in situ.

The effects of glucagon and insulin on glucose production were explored directly using the isolated perfused liver of the Goto-Kakizaki (GK) rat, an animal model of type-2 diabetes. In the perfused liver of control rats, infusion of glucagon (0.06-1.0 nM) into the portal vein dose-dependently increased glucose output. In the GK rat liver, in which the intracellular distribution of glycogen was heterogeneous, basal glucose output during perfusion was significantly higher than in control, whereas the effect of glucagon on the maximum glucose output was not different. Infusion of insulin inhibited the glucagon-induced hepatic glucose output by 30-40% in control livers, but had no effect on that from the GK rat liver. The increase in hepatic cAMP content after glucagon infusion was antagonized by insulin in control livers, but not in the livers of GK rats. These results indicate that the antagonistic effect of insulin on glucagon-induced hepatic glucose production was attenuated in the isolated liver of the GK rat and suggest that this insulin resistance appeared in the signal transduction process of glucagon upstream from cAMP production.

Animals↗

PubMed2001

Pivotal role of tyrosine phosphatase SHP-1 in AT2 receptor-mediated apoptosis in rat fetal vascular smooth muscle cell.

OBJECTIVE: To examine the possible crosstalk and the roles of angiotensin (Ang) II type 1 (AT1) and type 2 (AT2) receptors in the control of apoptosis in fetal vascular smooth muscle cells (VSMCs). METHODS: Fetal VSMCs were prepared from rat fetal aorta at embryonic day 20. Expression of Ang II receptors was measured by a radioligand binding assay. Apoptotic changes were assessed by caspase 3 activity and chromatin dye staining. Regulation of extracellular signal-regulated kinase (ERK) activity via Ang II receptors was analysed by determining phosphorylated ERK with Western blot. Ang II receptor-mediated activation of tyrosine phosphatase SHP-1 was assessed by protein tyrosine phosphatase assay. RESULTS: The expression of AT1 and AT2 receptors was approximately 70%: 30% per cell. Serum depletion induced apoptosis in fetal VSMCs and selective AT1 receptor stimulation attenuated the apoptotic changes, whereas selective AT2 receptor activation enhanced apoptosis. Ang II increased ERK phosphorylation, which was inhibited by addition of the AT1 receptor-specific antagonist CV11974, but enhanced by addition of the AT2 receptor-specific antagonist PD123319, suggesting that activation of AT2 receptor attenuated the AT1 receptor-mediated ERK phosphorylation. Moreover, we demonstrated that AT2 receptor stimulation activated SHP-1 in fetal VSMCs, whereas AT1 receptor stimulation did not. Transient transfection of a dominant-negative SHP-1 mutant into rat fetal VSMCs resulted in a significant decrease of the AT2 receptor-mediated inhibition of ERK phosphorylation and attenuated the proapoptotic effect of AT2 receptor. CONCLUSION: These results indicate that a crosstalk between AT1 and AT2 receptors regulates the survival of fetal VSMCs and substantiate SHP-1 as a key molecule in AT2 receptor signaling.

Analysis of Variance↗

PubMed2001

In vivo electroporation-mediated transfer of interleukin-12 and interleukin-18 genes induces significant antitumor effects against melanoma in mice.

Direct intratumoral transfection of cytokine genes was performed by means of the in vivo electroporation as a novel therapeutic strategy for cancer. Plasmid vectors carrying the firefly luciferase, interleukin (IL)-12 and IL-18 genes were injected into established subcutaneous B16-derived melanomas followed by electric pulsation. When plasmid vectors with Epstein--Barr virus (EBV) nuclear antigen 1 (EBNA1) gene were employed, the expression levels of the transgenes were significantly higher in comparison with those obtained with conventional plasmid vectors. In consequence of the transfection with IL-12 and IL-18 genes, serum concentrations of the cytokines were significantly elevated, while interferon (IFN)-gamma also increased in the sera of the animals. The IL-12 gene transfection resulted in significant suppression of tumor growth, while the therapeutic effect was further improved by co-transfection with IL-12 and IL-18 genes. Repetitive co-transfection with IL-12 and IL-18 genes resulted in significant prolongation of survival of the animals. Natural killer (NK) and cytotoxic T lymphocyte (CTL) activities were markedly enhanced in the mice transfected with the cytokine genes. The present data suggest that the cytokine gene transfer can be successfully achieved by in vivo electroporation, leading to both specific and nonspecific antitumoral immune responses and significant therapeutic outcome.

Animals↗

PubMed2001

Induction of brain-derived neurotrophic factor by convulsant drugs in the rat brain: involvement of region-specific voltage-dependent calcium channels.

A high level of hippocampal brain-derived neurotrophic factor (BDNF) in normally aged as compared with young rats suggests that it is important to maintain a considerable level of hippocampal BDNF during aging in order to keep normal hippocampal functions. To elucidate possible mechanisms of endogenous BDNF increase, changes in levels of BDNF were studied in the rat brain following systemic administration of various convulsant agents; excitotoxic glutamate agonists, NMDA, kainic acid and (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA); GABA receptor antagonists, picrotoxin, pentylenetetrazole (PTZ) and lindane (gamma-hexachlorocyclohexane); and L-type voltage-dependent calcium channel agonist, BAY-K 8644. Kainic acid and AMPA, but not NMDA, caused remarkable increases in BDNF protein in the rat hippocampus and entorhinal cortex. Picrotoxin, PTZ and lindane stimulated BDNF production in the entorhinal cortex and also in the hippocampus of rats showing very severe convulsions. On the other hand, BAY-K 8644 treatment increased BDNF levels in the neocortex and entorhinal cortex. Maximal levels of BDNF protein were observed at 12--24 h, 8--16 h and 6 h following administration of kainic acid, PTZ and BAY-K 8644, respectively. Kainic acid stimulated BDNF synthesis in presynaptic hippocampal granule neurons, but not in postsynaptic neurons with its receptors, while PTZ and BAY-K 8644 produced the same effects in postsynaptic neurons in the entorhinal cortex (in granule neurons in the hippocampus) and in the whole cortex, respectively. Nifedipine inhibited almost completely BAY-K 8644, but not PTZ, effects. omega-Conotoxin GVIA and DCG-IV partially blocked kainic acid-induced enhancement of BDNF, indicating involvement of L-type and N-type voltage-dependent calcium channels, respectively. In addition, BDNF levels in the hippocampus of mice deficient in D-myo-inositol-1,4,5-triphosphate receptor gene were scarcely different from those in the same region of controls, suggesting little involvement of intracellular calcium increase through this receptor. BAY-K 8644, but not kainic acid or PTZ, stimulated the phosphorylation of cyclic AMP responsive element binding protein. Our results indicate convulsant-dependent stimulation of BDNF production and involvement of region-specific voltage-dependent calcium channels.

Animals↗

PubMed2001

Angiotensin converting enzyme inhibitor restrains inflammation-induced vascular injury in mice.

OBJECTIVES: Recent advances in molecular genetics made the mouse model important for studying the genetic basis of hypertension and vascular diseases such as the components of the renin-angiotensin system. This study was undertaken to investigate the role of angiotensin converting enzyme (ACE) in the mouse vascular injury model. DESIGN AND METHODS: Inflammation-induced vascular injury was created by placing a polyethylene cuff around the femoral artery of 12-14-week-old male FVB/N mice. Cuffed arteries were harvested and applied to reverse transcriptase-polymerase chain reaction analysis and immunohistochemistry for ACE. Subsequently, the effects of an ACE inhibitor, perindopril (3 mg/kg per day), on neointimal thickening were examined 2 weeks after cuff placement The influence of a nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME, 20 mg/kg per day) on the effects of perindopril was also examined. RESULTS: ACE mRNA expression increased in a time-dependent manner up to 2 weeks after cuff placement. Immunoreactive ACE was localized in the endothelium in the intact artery, while positive staining was observed in the medial and neointimal layer as well as in the periadventitial region of the cuffed artery. The intimamedia area ratio was significantly decreased by perindopril treatment (vehicle, 0.75+/-0.10; perindopril, 0.32+/-0.04; P< 0.05). The effect of perindopril was abrogated by coadministration of L-NAME whereas L-NAME alone did not affect the intima-media ratio (L-NAME, 0.66+/-0.11; perindopril + L-NAME, 0.72+/-0.09). CONCLUSIONS: This study provides evidence that ACE plays a role in cuff-induced neointimal thickening in mice. Nitric oxide may contribute, at least in part, to the inhibitory effects of perindopril.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2001

Chemotherapy-induced unconjugated hyperbilirubinemia caused by a mutation of the bilirubin uridine-5'-diphosphate-glucuronosyltransferase gene.

Chemotherapy for malignant neoplasms sometimes causes unconjugated hyperbilirubinemia in the absence of liver dysfunction. We analyzed the association of chemotherapy-induced hyperbilirubinemia with mutations of the bilirubin uridine-5'-diphosphate (UDP)-glucuronosyltransferase gene (UGT1A1) from two leukemic patients in whom chemotherapy resulted in a hyperbilirubinemic response. We isolated genomic DNA from peripheral blood samples and amplified UGT1A1 by polymerase chain reaction. The amplified DNA fragments were analyzed by direct sequencing. The genes of the two patients revealed an identical heterozygous missense mutation in exon 1 (211G-->A: G71R). This UGT1A1 mutation may be the basis of chemotherapy-induced unconjugated hyperbilirubinemia.

Adolescent↗

PubMed2001

Type II (adult onset) citrullinaemia: clinical pictures and the therapeutic effect of liver transplantation.

OBJECTIVE: Adult onset type II citrullinemia is an inherited disorder of amino acid metabolism caused by a deficiency of liver specific argininosuccinate synthetase activity. Most of the patients with this disease were reported in Japan and therefore, this disease has not been well recognised outside this country. The detailed clinical pictures of the patients with type II citrullinaemia are reported and their outcomes after liver transplantation referred to. METHODS: Ten patients with this disease were evaluated. Seven of them underwent liver transplants using a graft obtained from a healthy family member. RESULTS: There were six men and four women; the age of onset of encephalopathy ranged from 17 to 51 years. The initial symptom in nine patients was sudden onset disturbance of consciousness, and one patient had long been regarded as having a chronic progressive psychotic illness. High concentrations of plasma citrulline and ammonia were commonly seen on admission. Although brain CT or MRI lacked any consistent findings, the EEG was abnormal in all patients, showing diffuse slow waves. Additionally, in five patients chronic pancreatitis preceded the onset of encephalopathy. After liver transplantation the metabolic abnormalities, including abnormal plasma concentrations of citrulline and ammonia, were immediately corrected and all neuropsychic symptoms soon disappeared, except for impaired cognitive function in one patient. Six out of these seven patients returned to their previous social lives, including work. CONCLUSIONS: The clinical concept of adult onset type II citrullinaemia coincides well with the range of hepatic encephalopathy, and liver transplantation is a very promising therapeutic approach.

Adolescent↗